the animation cursor is playing in a stepped movement. Even if there are no keyframes put the time-cursor is moving the same way. my fps rate is 30is
your fps are very low that could mean a hardware limitation, probably your system does not have the requirements to work at full with blender or could be a bug. check the minimun requirements to run blender HERE

If you wanna see your animation at full speed, render a preview (Go to View &gt; Viewport Render Animation) Here is a video explaining that